option(BUILD_DOXYGEN_DOC "Build doxygen documentation" OFF)

# check if Doxygen is installed
find_package(Doxygen)
if(DOXYGEN_FOUND)
  # set input and output files
  set(DOXYGEN_IN ${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile.in)
  set(DOXYGEN_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)

  # request to configure the file
  configure_file(${DOXYGEN_IN} ${DOXYGEN_OUT} @ONLY)
  message("Doxygen build started")

  # note the option ALL which allows to build the docs together with the
  # application
  add_custom_target(
    doc_doxygen ALL
    COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_OUT}
    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
    COMMENT "Generating API documentation with Doxygen"
    VERBATIM
  )
else(DOXYGEN_FOUND)
  message("Doxygen need to be installed to generate the doxygen documentation")
endif(DOXYGEN_FOUND)
